Consider two groups of students: $B_{1}$, students who received high scores on tests, and $B_{2}$, students who received low scores on tests. In group $B_{1}, 80 \%$ study more than 25 hours per week, and in group $B_{2}, 40 \%$ study more than 25 hours per week. What is the overinvolvement ratio for high study levels in high test scores over low test scores?